package cn.javass.framework.web.wrapper;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.io.Serializable;
import java.util.*;

public class SessionMap extends AbstractMap implements Serializable {

    protected HttpSession session;
    protected Set entries;
    protected HttpServletRequest request;
    
    public SessionMap(HttpServletRequest request) {
        // note, holding on to this request and relying on lazy session initalization will not work
        // if you are running your action invocation in a background task, such as using the
        // "exec-and-wait" interceptor
        this.request = request;
        this.session = request.getSession(false);
    }

    public void invalidate() {
        if (session == null) {
            return;
        }


        synchronized(session) {
            session.invalidate();
            session = null;
            entries = null;
        }
    }


    public void clear() {
        if (session == null ) {
            return;
        }

        synchronized (session) {
            if (entries != null ) {
                for ( Iterator iter = entries.iterator(); iter.hasNext(); ) {
                    Object key = iter.next();
                    session.removeAttribute(key.toString());
                }
                entries = null;
            }
        }
    }

   
    public Set entrySet() {
        if (session == null) {
            return Collections.EMPTY_SET;
        }

        synchronized (session) {
            if (entries == null) {
                entries = new HashSet();

                Enumeration enumeration = session.getAttributeNames();

                while (enumeration.hasMoreElements()) {
                    final String key = enumeration.nextElement().toString();
                    final Object value = session.getAttribute(key);
                    entries.add(new Map.Entry() {
                        public boolean equals(Object obj) {
                            Map.Entry entry = (Map.Entry) obj;

                            return ((key == null) ? (entry.getKey() == null) : key.equals(entry.getKey())) && ((value == null) ? (entry.getValue() == null) : value.equals(entry.getValue()));
                        }

                        public int hashCode() {
                            return ((key == null) ? 0 : key.hashCode()) ^ ((value == null) ? 0 : value.hashCode());
                        }

                        public Object getKey() {
                            return key;
                        }

                        public Object getValue() {
                            return value;
                        }

                        public Object setValue(Object obj) {
                            session.setAttribute(key.toString(), obj);

                            return value;
                        }
                    });
                }
            }
        }

        return entries;
    }

 
    public Object get(Object key) {
        if (session == null) {
            return null;
        }

        synchronized (session) {
            return session.getAttribute(key.toString());
        }
    }

    public Object put(Object key, Object value) {
        synchronized (this) {
            if (session == null) {
                session = request.getSession(true);
            }
        }

        synchronized (session) {
            entries = null;
            session.setAttribute(key.toString(), value);

            return get(key);
        }
    }

   
    public Object remove(Object key) {
        if (session == null) {
            return null;
        }

        synchronized (session) {
            entries = null;

            Object value = get(key);
            session.removeAttribute(key.toString());

            return value;
        }
    }
}
